WARNING **:
这时候可以考虑如下解决方案：
1. The first and easiest way to work around this security issue is to add yourself to the netdev group. The default security policy permits access for that group.
2、
Change the default policy context in both
/etc/dbus-1/system.d/NetworkManager.conf
and
/etc/dbus-1/system.d/nm-applet.conf
so it says 'allow' instead of 'deny'.
Then restart dbus
sudo /etc/init.d/dbus restart
and launch the applet
nm-applet这样就应该可以了。